461 research outputs found
Third case of the Cyclic Coloring Conjecture
The Cyclic Coloring Conjecture asserts that the vertices of every plane graph
with maximum face size D can be colored using at most 3D/2 colors in such a way
that no face is incident with two vertices of the same color. The Cyclic
Coloring Conjecture has been proven only for two values of D: the case D=3 is
equivalent to the Four Color Theorem and the case D=4 is equivalent to
Borodin's Six Color Theorem, which says that every graph that can be drawn in
the plane with each edge crossed by at most one other edge is 6-colorable. We
prove the case D=6 of the conjecture
Cyclic Coloring of Plane Graphs with Maximum Face Size 16 and 17
Plummer and Toft conjectured in 1987 that the vertices of every 3-connected
plane graph with maximum face size D can be colored using at most D+2 colors in
such a way that no face is incident with two vertices of the same color. The
conjecture has been proven for D=3, D=4 and D>=18. We prove the conjecture for
D=16 and D=17
Graphs with bounded tree-width and large odd-girth are almost bipartite
We prove that for every and every , there exists such
that every graph with tree-width at most and odd-girth at least has
circular chromatic number at most
Navigating International, Interdisciplinary, and Indigenous Collaborative Inquiry
This report describes how multiple community constituents came together with university researchers to develop a shared agenda for studying young indigenous people in five international circumpolar communities. The paper focuses on the setup and process of an initial face-to-face methodological planning workshop involving youth and adult community members and academics. Members of Yupâik, Inupiat, Eveny, Inuit, and SĂĄmi communities from Siberia to Norway participated in the workshop and engaged in negotiations to arrive at shared research interests. This was essential since the ultimate goal of the research is translational and transformative, spurring social action in communities. Describing the beginning stage of this project and the underlying participatory methodology offers insight into how the approach engaged community members with varying degrees of sustained interest and practical success. It, therefore, articulates a methodological approach for international community-based participatory research
First results from the OSQAR photon regeneration experiment: No light shining through a wall
A new method to amplify the photon-axion conversions in magnetic field is
proposed using a buffer gas at a specific pressure. As a first result, new
bounds for mass and coupling constant for purely laboratory experiments aiming
to detect any hypothetical scalars and pseudo-scalars which can couple to
photons were obtained at 95% confidence level, excluding the PVLAS result newly
disclaimed.Comment: 4 pages, 5 figure
DNA-binding by Haemophilus influenzae and Escherichia coli YbaB, members of a widely-distributed bacterial protein family
BACKGROUND: Genes orthologous to the ybaB loci of Escherichia coli and Haemophilus influenzae are widely distributed among eubacteria. Several years ago, the three-dimensional structures of the YbaB orthologs of both E. coli and H. influenzae were determined, revealing a novel tweezer -like structure. However, a function for YbaB had remained elusive, with an early study of the H. influenzae ortholog failing to detect DNA-binding activity. Our group recently determined that the Borrelia burgdorferi YbaB ortholog, EbfC, is a DNA-binding protein. To reconcile those results, we assessed the abilities of both the H. influenzae and E. coli YbaB proteins to bind DNA to which B. burgdorferi EbfC can bind.
RESULTS: Both the H. influenzae and the E. coli YbaB proteins bound to tested DNAs. DNA-binding was not well competed with poly-dI-dC, indicating some sequence preferences for those two proteins. Analyses of binding characteristics determined that both YbaB orthologs bind as homodimers. Different DNA sequence preferences were observed between H. influenzae YbaB, E. coli YbaB and B. burgdorferi EbfC, consistent with amino acid differences in the putative DNA-binding domains of these proteins.
CONCLUSION: Three distinct members of the YbaB/EbfC bacterial protein family have now been demonstrated to bind DNA. Members of this protein family are encoded by a broad range of bacteria, including many pathogenic species, and results of our studies suggest that all such proteins have DNA-binding activities. The functions of YbaB/EbfC family members in each bacterial species are as-yet unknown, but given the ubiquity of these DNA-binding proteins among Eubacteria, further investigations are warranted
Gendered endings: Narratives of male and female suicides in the South African Lowveld
This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s11013-012-9258-y. Copyright @ Springer Science+Business Media, LLC 2012.Durkheimâs classical theory of suicide rates being a negative index of social solidarity downplays the salience of gendered concerns in suicide. But gendered inequalities have had a negative impact: worldwide significantly more men than women perpetrate fatal suicides. Drawing on narratives of 52 fatal suicides in Bushbuckridge, South Africa, this article suggests that Bourdieuâs concepts of âsymbolic violenceâ and âmasculine dominationâ provide a more appropriate framework for understanding this paradox. I show that the thwarting of investments in dominant masculine positions have been the major precursor to suicides by men. Men tended to take their own lives as a means of escape. By contrast, women perpetrated suicide to protest against the miserable consequences of being dominated by men. However, contra the assumption of Bourdieuâs concept of âhabitusâ, the narrators of suicide stories did reflect critically upon gender constructs
- âŠ